Detergent solutions

ABSTRACT

THE DISINFECTING ACTIVITY OF CHLORHEXIDINE OR DERIVATIVES THEREOF WHEN USED IN A DETERGENT SOLUTION CONTAINING A BETAINE IS MAINTAINED BY ADDING UREA OR A DERIVATIVE THEREOF TO THE DETERGENT/DISINFECTANT SOLUTION.

United States Patent "ice US. Cl. 252106 4 Claims ABSTRACT OF THEDISCLOSURE The disinfecting activity of chlorhexidine or derivativesthereof when used in a detengent solution containing a betaine ismaintained by adding urea or a derivative thereof to the detergent/disinfectant solution.

BACKGROUND OF THE INVENTION Field of the invention This inventionrelates to detergent solutions which have a disinfectant action and isconcerned specifically with those detergent solutions in which aguanidine derivative having disinfectant properties is provided.

DESCRIPTION OF THE PRIOR ART The disinfecting activity of guanidinederivatives such as chlorhexidine, i.e. 1:6-di- (N-p-chlorophenyldiguanido- N hexane, and the gluconate salt thereof arewell known. The surface active properties of betaines are also wellknown. It has :been found, however, that when a disinfectant such aschlorhexidine is mixed with a betaine, the disinfecting activity of thedisinfectant is considerably reduced.

It is accordingly an object of the present invention to provide adetergent solution which includes, as disinfectant, chlorhexidine or asalt or derivative thereof and an activity-maintaining agent formaintaining the activity of the disinfectant when admixed with asurfactant.

SUMMARY OF THE INVENTION Urea or an alkyl substituted urea is added to adetergent solution containing a betaine and a disinfectant selected fromthe group consisting of chlorhexidine, derivatives of chlorhexidine andthe salts thereof to maintain the activity of the disinfectant.

DESCRIPTION OF THE PREFERRED EMBODIMENTS The preferred disinfectants arechlorhexidine and the polyhydroxy aliphatic carboxylic acid saltsthereof such as the gluconate.

A preferred detergent solution comprises between 0.1% and 1.5% by weightof chlorhexidine or a salt thereof, between 1.0% and 15% by weight of abetaine and between 2% and 15% by weight of urea or an alkyl substitutedurea. The preferred betaine is pendecamaine, i.e.N,N-dimethyl(3-palmitamido propyl)aminoacetic acid. Chlorhexidine saltswhich can be used include chlorhexidine acetate and chlorhexidinehydrochloride. A thickening agent such as methyl or hydroxyethylcellulose may be added and a sequestering agent such as ethylenediaminetetracetic acid may also be added. The detergent solution may alsoinclude a moisturising agent such as propylene glycol and/or a perfumeor colourant.

More specific examples of the invention will now be described.

Two disinfectant solutions were prepared and disinfectant solution acontained 0.75% by weight chlorhexidine gluconate, 5% by weight ofpendecamaine, 0.5% by weight of hydroxyethyl cellulose and by weighturea. Solution b contained the same amount of chlorhexi- 3,694,366Patented Sept. 26, 1972 dine gluconate, pendecamaine and hydroxyethylcellulose but no urea was included in the composition.

Samples of solution a and of solution b were added to test samplescontaining a gram-negative organism such as pseudomonas aeruginosa andsamples were then taken from the solution of organisms and disinfectantand these samples were then exposed and tested for micro-organismgrowth. It was found that, using solution a, a 10 minute treatment ofthe micro-organisms with the disinfectant solution was suificient toprevent growth of the microorganisms whereas, with solution b, i.e.without the urea, a treatment time of at least 1 hour was necessary toprevent growth of the micro-organisms.

In a further test a solution c was prepared and this included 0.5% byweight chlorhexidine gluconate, 10% by weight of pendecamaine, 0.5% ofhydroxyethyl cellulose and 5% by weight of urea it was found that, byincreasing the amount of the pendecamaine and reducing the amount ofchlorhexidine gluconate, the time for which the micro-organisms had tobe treated with the disinfectant to obtain no growth conditions wasreduced.

Tests carried out using other chlorhexidine compounds such aschlorhexidine itself and chlorhexidine acetate and using other betainesshow that, when urea or a substituted urea and preferably a lower alkylsubstituted urea such as dimethyl urea or diethyl urea, the length ofthe treatment time required to obtain no growth conditions isconsiderably reduced as compared with the conditions obtained when theurea or derivative thereof is not added.

In general it has been found that the disinfecting activity of thechlorhexidine gluconate or other chlorhexidine derivative issubstantially the same as it would be in the absence of the betainedetergent. The disinfectant/detergent compositions of the presentinvention are intended to be used instead of the hexachlorophenedisinfectant/ detergent compositions at present in use. A majordisadvantage of hexachlorophene based detergent compositions is thatgram-negative organisms are either not affected or growth thereof ismerely prevented. The chlorhexidine derivatives have a wider range ofactivity than the hexachlorophene based compositions. A furtherdisadvantage of the hexachlorophene based detergents is thathexachlorophene is most active when used in combination with an alkalinesoap and it has been found that alkaline detergents have a greatertendency to cause skin irritation than acid detergents. Skin has a pH ofthe order of 5 to 5.5 and a preferred pH of the chlorhexidine baseddetergents is thus of the same order.

In a further example of the present invention a detergent solution wasprepared by firstly producing a gel from 0.5 part by weight ofhydroxyethyl cellulose and water. Ten parts by weight of urea weredissolved in water and the urea solution mixed with the gel of thehydroxyethyl cellulose. 1.5 parts by weight of propylene glycol was thenadded to this mixture, followed by 5.0 parts by weight of pendecamaineand 0.75 part by weight of chlorhexidine gluconate. 0.005 part by weightof a perfume were then added and an appropriate amount of a colourantadded and the total solution made up with water to parts by weight. ThepH of the solution is adjusted so as to be approximately 6.5.

A testing procedure was then carried out to establish the efficiency ofthe above detergent/ disinfectant composition. Tests were carried out ona number of subjects and the procedure was as follows:

(1) The subjects rinse their hands for 10 seconds under running tapwater and dry them on a sterile towel.

(2) The subjects then rinse their hands using 100 mils of a standardsterile rinse solution which consists of a quarter strength ringerssolutions and the rinsing procedure is standardised as follows:

The hands are wetted with the rinse solution. They are then rubbedtogether palm to palm with three strokes. The left hand palm is thenused to rub the back of the right hand with three strokes, whilst at thesame time the fingers are interlaced. The right palm is then used to rubthe back of the left hand in the same way. The rinse solution is drainedinto a container and a one mil sample of it is transferred to a cultureplate whilst a series of 10 fold dilutions is also made, one mil samplesof each being transferred to culture plates.

(3) The subject then washed the hands with three to four mils of thedetergent/disinfectant solution set out above rapidly to remove tracesof the rinse solution and dries then on a sterile towel.

(4) About 7 mils of the detergent/disinfectant solution as set out aboveare then added to the dry hands and the composition is massaged into theskin for 2 minutes, particular attention being paid to the areas aroundthe finger nails. Tap water is then added and the hands washed for about15 seconds. They are then dried on a sterile towel.

(5) The rinse procedure as set out at 2 above is repeated.

(6) During the following 24 hours the hands are treated as at 4 above 8times, and at all other times when social washing is carried out, thedetergent/disinfectant solution of the invention is used in place ofsoap.

(7) After the 8th treatment, the rinse procedure as at 2 above is againcarried out.

For some of the subjects the procedure as set out at 4 above is effected8 times a day for 7 days after which the rinse procedure as per step 2is again carried out.

After incubation the number of colonies per plate are mounted and thecounts obtained are shown on the following chart. In each case sample 1is the sample obtained after the first rinsing, i.e. before anytreatment with the detergent/disinfectant solution of the presentinvention. Sample 2 is the sample obtained after washing once with thedetergent/ disinfectant solution of the present invention, sample 3 isthe sample obtained after 24 hours treatment and sample 4 is the sampleobtained after 7 days treatment. The letters TNTC indicates that thenumber of organisms incubated was too numerous to count.

The results above show the considerable disinfecting activity of thecompositions of the present invention and the advantages that would beobtained by, for example, a surgeon continually using the compositionare clearly demonstrated.

To ensure that any of the detergent/ disinfectant composition which mayremain on the hands does not prevent free growth of micro-organisms onthe culture plate, the rinse solution contains inactivators. To showthat these inactivators are effective an inactivation control test hasbeen carried out as follows: dilutions of staphylococcus aureus areprepared and one mil of this is added to mils of inactivating solutioncontaining 3.5 mils of the detergent/disinfectant solution prepared asset out above. One mil samples of the diluted staphylococcus aureus arealso added to 100 mils of inactivating solution not containing thedisinfectant/detergent solution. Samples are then taken from theinactivating solution with and without the detergent/ disinfectantsolution added and similar counts are obtained from both samples.

In the preferred detergent/ disinfectant composition as set out abovethe chlorhexidine gluconate can be 'varied within the range of from 0.1%to 1. 5%, the betaine can be varied between the range of from 0.1% to15% and the urea can be varied within the range of from 2% to 15 Thepropylene glycol acts as a humectant or moisturising agent and assistsin keeping the solution clear. The cellulose derivative acts as athickening agent.

Ethylenediaminetetracetic acid or derivatives thereof can be added andit has been found that the addition of ethylenediaminetetracetic acid orderivatives thereof improves the bacteriological effect of thedisinfectant but the addition thereof has the disadvantage that there isan increased tendecy to skin irritation. If ethylenediaminetetraceticacid or a derivative thereof is to be added, the amount thereof willnormally be between 0.1% and 0.5% by weight.

I claim:

1. An aqueous detergent solution consisting essentially of between 0.1%and 1.5% by weight of a disinfectant selected from the group consistingof 1:6-di-(N -p-chloropheny1diguanido-N hexane and the gluconate andacetate salts thereof, between 1.0% and 15% by weight of N,N- dimethyl(3-palmitamido-propyl) aminoacetic acid, and between 2% and 15 by weightof an activity-maintaining agent selected from the group consisting ofurea and lower alkyl substituted ureas for maintaining the disinfectingactivity of the disinfectant.

2. A detergent solution according to claim 1 wherein the amount byweight of disinfectant in the detergent solution is between 0.5% and0.75% by weight.

3. A detergent solution according to claim 1 in which the amount byweight of said N,N-dimethyl (3-palmitamido-propyl)aminoacetic acid isbetween 5% and 10% by weight.

4. A detergent solution according to claim 1 wherein the amount byWeight of the activity-maintaining agent is between 5% and 10% byweight.

References Cited UNITED STATES PATENTS 2,990,425 6/1961 Senior 2605012,388,614 11/1945 Kirby et a1 424-329 XR 3,183,230 5/1965 Shapiro et al.260244 3,489,686 1/ 1970 Parran 252106 FOREIGN PATENTS 1,040,543 9/1966Great Britain. 1,109,431 4/ 1968 Great Britain.

159,111 8/1952 Australia.

963,907 7/ 1964 Great Britain.

LEON D. ROSDOL, Primary Examiner P. E. WILLIS, Assistant Examiner U.S.Cl. X.R.

